Beneficial or Bad News? A Guide to Common Arthropods in Lamoni

Beneficial or Bad News? A Guide to Common Arthropods in Lamoni


Written by: Jenna Cox '17

Spring may be finally arriving for good in Lamoni! We had an unusual few warm days prior to Graceland’s spring break at the end of February; It was 75°. But then, two days later, it started to snow! The brief balmy weather tricked us all. It even tricked some of the trees around here; some started to bud early, but then the temperature dropped back down to freezing.

When the temperature climbs back up into a comfortable range (the recent rains and warmth tell me it may be doing so for good!), all the insects that have overwintered will start to emerge and quickly multiply. Some of these little creatures are beneficial to humans, and some are harmful, but they all play an important role in our local ecosystems.

I have compiled a photographic collection of some of the arthropods we are likely to start seeing in Lamoni during the coming spring and summer. In anticipation of the warm season, Graceland Sustainability is preparing to plant new veggies in the hoop house, and there is no doubt that bugs will return to the hoop as well. We hope that most of them will be beneficial to our gardens, but even if they are not, there will surely be other arthropods present which will take care of some of the pests we encounter. There are plenty of checks and balances in the tiny world beneath our feet, and they are all pretty amazing!

Bagworm Moth (Thyridopteryx Ephemeraeformis)

The bagworm moth is an interesting little critter, and you may have noticed their strange bags hanging in your yard long after all living insects have disappeared for the winter. There is a bush in the Tess Morgan courtyard that is covered in them; I originally mistook them for dead leaves that refused to blow away. The larvae of the bagworm moth construct a bag out of silk and cover it with the leaves and twigs of the host plant they live and feed upon. They mostly eat evergreen plants, but will eat some deciduous kinds as well, and in large numbers they can be considered a pest as they defoliate trees and bushes.

The larvae will carry the bag around on its body until it is fully grown, and then it will attach itself to a branch or other sturdy surface and seal itself up, as is pictured. This bagworm has long been hanging on the outside wall of the Fitz, beside the evergreen bushes it lived upon, as is evident by the dry needles stuck all over the bag. The adult moth will emerge from this casing after a pupa stage takes place inside, sometimes happening over the winter. The adult female bagworm moth is actually flightless!

  

Chinese Mantis (Tenodera Sinensis) and Carolina Mantis (Stagmomantis Carolina)

There are two kinds of praying mantis found in Iowa: the Chinese mantis and the Carolina mantis. The Chinese mantis (picture 1) can be identified by the green stripe along its long brown body and, if you get close enough, the vertical stripes on its face. Many of the mantids I have seen on the Graceland campus are Chinese mantids, and they can grow to be 4.25 inches long. The Carolina mantis is a little bit smaller and has a speckled brown body, with green legs (picture 2).

Mantids are excellent hunters of just about any insect, which means they can take care of pests in your garden. However, they will also happily munch on butterflies, bees and other insects we like to keep around. They will eat anything they can catch with their quick, sharp forelimbs, so they do not discriminate between the insects that either harm or help humans.

  1. Fun fact: they are the only insect that can truly rotate their head!
  2. Fun fact: mantids can fly short distances! I have seen one do it once, and it was amusing, as it flew with its forelimbs extended out in front of it, like a little Superman.

In the late summer and early fall, the female mantids will lay foamy-looking egg cases to protect their eggs before dying when the winter cold comes. The female Chinese mantis in the first photo made her home in a bush beside the Admin building last fall, and she left at least two egg cases behind. Tiny nymphs will emerge from them after the winter is over, innately prepared to hunt miniscule insects all on their own. Hopefully some of these interesting insects will re-appear on campus soon. It is always a treat to see them!

Differential Grasshopper (Melanoplus Differentialis)

These grasshoppers are likely the largest you will see in Iowa. They are a couple inches long, brown-green, and have a black fishbone pattern on their powerful hind legs. They are found in habitats all throughout the Midwest, such as grassland, prairie, gardens, and along roads and streams.

Differential grasshoppers will eat multiple kinds of plant life, including crops such as soybean, corn, small grains and even the leaves of fruit trees. For this reason, if they gather in large numbers, they can cause big damage to commercial crops. However, they also love to eat ragweed, which is a nasty weed that takes over and causes pollen allergy problems for some people (myself included) during the late summer and fall. These grasshoppers are also a great food source for several types of native reptiles, amphibians, birds and even some small mammals.

Ground Beetle Larvae

This was an insect I had never seen before, and it took me a bit of searching to figure out what it was. This is the larval stage of a ground beetle! Ground beetles are beneficial in our gardens, because many of them are carnivorous, eating pests in our gardens such as caterpillars, slugs, and snails. Ground beetles have large mandibles (jaws) that they use to attack and devour other insects. After they go through the larval stage, pictured, they will turn into a pupa – much like moths and butterflies do – before emerging as an adult beetle. A lot of beetle species go through this process, and our gardens are much better for it.

Squash Bug (Anasa Tristis)

Squash bugs were a real problem for us in Graceland Sustainability last fall. We were growing miniature pumpkins (detailed in an earlier blog post) and another kind of squash, and these nasty little bugs made themselves right at home in our hoop house. If you look closely, you can see in the photo how they damage squash crops.

They have a thin, sharp mouthpart that they insert into the vines and fruit of vegetables in the squash family (the “cucurbits”). They suck the juices and sap from the plants, which can destroy crops if they are present in large numbers. Squash bugs are part of the “true bug” order, which also includes aphids, cicadas and leafhoppers. They have a shield-like shape, and they are related to stink bugs, so if they are disturbed, they smell pretty nasty. They are definitely not an insect we want in the hoop house.

Black and Yellow Garden Spider (Argiope Aurantia)

Luckily, there are some small warriors on our side in the hoop house. Black and yellow garden spiders are beneficial arachnids that can be found all around the United States in sunny, quiet gardens. They are easily identified by their bright yellow and black abdomens and the orange stripes on their legs. Their webs are just as unique, as they often have a solid zig-zag shape down the center of them. I called these “zipper spiders” while growing up in Texas.

They will eat any flying insects that hang out in your garden and happen to get into their web (squash bugs can indeed fly, heh heh). These spiders are not dangerous to humans, and are likely to flee if you happen to disturb them. The females lay a papery brown egg sac to one side of the web before dying at the end of the summer. This female lived in the corner of our hoop house in the fall, and we hope that the egg sack she laid is full of beneficial babies for our upcoming vegetable gardens. We need all the natural protection we can get, as we prefer not to use pesticides in our hoop house when we can avoid it!

As spring continues to approach, more and more insects will emerge. Keep an eye out for them as you walk across campus! Be sure to also keep an eye out for our next blog post, which will be about some of our most valuable arthropod allies when it comes to the health of our crops and native plant life. Happy spring from everyone in Graceland Sustainability!

Information adapted from: